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Special Issue "Magnetic Nanoparticles 2013"

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A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Material Sciences and Nanotechnology".

Deadline for manuscript submissions: closed (15 July 2013)

Special Issue Editor

Guest Editor
Prof. Dr. Jon Dobson

Department of Biomedical Engineering, Institute for Cell Engineering and Regenerative Medicine (ICERM), Primary Faculty, University of Florida, BMS J389, P.O. Box 116131, Gainesville, FL 32611, USA
Website | E-Mail
Fax: +1 352 273 9221

Special Issue Information

Dear Colleagues,

Magnetic micro- and nanoparticles have been used in biological and biomedical investigations since the 1920s when Heilbrunn and Seifritz first used the forces on these particles to examine the rheological properties of cells. Since that time, myriad uses for these particles have arisen and much progress has been made in synthesis techniques and bio-functionalization. Superparamagnetic iron oxides are routinely used in the clinic today as MRI contrast agents and are found in many pathology laboratories around the world where they are used for cell separation assays. More recent, novel uses include binding to specific cell receptors to control cell function and stem cell differentiation for tissue engineering and regenerative medicine, as well as magnetic targeting for drug and gene delivery, magnetic fluid hyperthermia, and other novel applications. This issue will cover a variety of topics related to the use of MNPs in biomedicine and examine both novel synthesis and bio-functionalization techniques as well as their current and future uses in biomedical research, diagnostics and therapy.

Prof. Dr. Jon Dobson
Guest Editor

Submission

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. International Journal of Molecular Sciences is an international peer-reviewed Open Access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF.

Keywords

  • magnetic nanoparticles
  • biomedical
  • superparamagnetic
  • SPIONs
  • tissue engineering
  • regenerative medicine
  • cancer therapy
  • gene therapy

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Published Papers (34 papers)

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Research

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Open AccessArticle Sustained Release of Prindopril Erbumine from Its Chitosan-Coated Magnetic Nanoparticles for Biomedical Applications
Int. J. Mol. Sci. 2013, 14(12), 23639-23653; doi:10.3390/ijms141223639
Received: 21 August 2013 / Revised: 27 October 2013 / Accepted: 1 November 2013 / Published: 3 December 2013
Cited by 4 | PDF Full-text (2194 KB) | HTML Full-text | XML Full-text
Abstract
The preparation of magnetic nanoparticles coated with chitosan-prindopril erbumine was accomplished and confirmed by X-ray diffraction, TEM, magnetic measurements, thermal analysis and infrared spectroscopic studies. X-ray diffraction and TEM results demonstrated that the magnetic nanoparticles were pure iron oxide phase, having a spherical
[...] Read more.
The preparation of magnetic nanoparticles coated with chitosan-prindopril erbumine was accomplished and confirmed by X-ray diffraction, TEM, magnetic measurements, thermal analysis and infrared spectroscopic studies. X-ray diffraction and TEM results demonstrated that the magnetic nanoparticles were pure iron oxide phase, having a spherical shape with a mean diameter of 6 nm, compared to 15 nm after coating with chitosan-prindopril erbumine (FCPE). Fourier transform infrared spectroscopy study shows that the coating of iron oxide nanoparticles takes place due to the presence of some bands that were emerging after the coating process, which belong to the prindopril erbumine (PE). The thermal stability of the PE in an FCPE nanocomposite was remarkably enhanced. The release study showed that around 89% of PE could be released within about 93 hours by a phosphate buffer solution at pH 7.4, which was found to be of sustained manner governed by first order kinetic. Compared to the control (untreated), cell viability study in 3T3 cells at 72 h post exposure to both the nanoparticles and the pure drug was found to be sustained above 80% using different doses. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessArticle Chitosan-Coated Magnetic Nanoparticles Prepared in One Step by Reverse Microemulsion Precipitation
Int. J. Mol. Sci. 2013, 14(10), 19636-19650; doi:10.3390/ijms141019636
Received: 31 May 2013 / Revised: 5 September 2013 / Accepted: 12 September 2013 / Published: 27 September 2013
Cited by 6 | PDF Full-text (535 KB) | HTML Full-text | XML Full-text
Abstract
Chitosan-coated magnetic nanoparticles (CMNP) were obtained at 70 °C and 80 °C in a one-step method, which comprises precipitation in reverse microemulsion in the presence of low chitosan concentration in the aqueous phase. X-ray diffractometry showed that CMNP obtained at both temperatures contain
[...] Read more.
Chitosan-coated magnetic nanoparticles (CMNP) were obtained at 70 °C and 80 °C in a one-step method, which comprises precipitation in reverse microemulsion in the presence of low chitosan concentration in the aqueous phase. X-ray diffractometry showed that CMNP obtained at both temperatures contain a mixture of magnetite and maghemite nanoparticles with ≈4.5 nm in average diameter, determined by electron microscopy, which suggests that precipitation temperature does not affect the particle size. The chitosan coating on nanoparticles was inferred from Fourier transform infrared spectrometry measurements; furthermore, the carbon concentration in the nanoparticles allowed an estimation of chitosan content in CMNP of 6%–7%. CMNP exhibit a superparamagnetic behavior with relatively high final magnetization values (≈49–53 emu/g) at 20 kOe and room temperature, probably due to a higher magnetite content in the mixture of magnetic nanoparticles. In addition, a slight direct effect of precipitation temperature on magnetization was identified, which was ascribed to a possible higher degree of nanoparticles crystallinity as temperature at which they are obtained increases. Tested for Pb2+ removal from a Pb(NO3)2 aqueous solution, CMNP showed a recovery efficacy of 100%, which makes them attractive for using in heavy metals ion removal from waste water. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessArticle Mixtures of l-Amino Acids as Reaction Medium for Formation of Iron Nanoparticles: The Order of Addition into a Ferrous Salt Solution Matters
Int. J. Mol. Sci. 2013, 14(10), 19452-19473; doi:10.3390/ijms141019452
Received: 17 May 2013 / Revised: 24 June 2013 / Accepted: 30 August 2013 / Published: 25 September 2013
Cited by 3 | PDF Full-text (5028 KB) | HTML Full-text | XML Full-text
Abstract
Owing to Mössbauer spectroscopy, an advanced characterization technique for iron-containing materials, the present study reveals previously unknown possibilities using l-amino acids for the generation of magnetic particles. Based on our results, a simple choice of the order of l-amino acids addition into a
[...] Read more.
Owing to Mössbauer spectroscopy, an advanced characterization technique for iron-containing materials, the present study reveals previously unknown possibilities using l-amino acids for the generation of magnetic particles. Based on our results, a simple choice of the order of l-amino acids addition into a reaction mixture containing ferrous ions leads to either superparamagnetic ferric oxide/oxyhydroxide particles, or magnetically strong Fe0-Fe2O3/FeOOH core-shell particles after chemical reduction. Conversely, when ferric salts are employed with the addition of selected l-amino acids, only Fe0-Fe2O3/FeOOH core-shell particles are observed, regardless of the addition order. We explain this phenomenon by a specific transient/intermediate complex formation between Fe2+ and l-glutamic acid. This type of complexation prevents ferrous ions from spontaneous oxidation in solutions with full air access. Moreover, due to surface-enhanced Raman scattering spectroscopy we show that the functional groups of l-amino acids are not destroyed during the borohydride-induced reduction. These functionalities can be further exploited for (i) attachment of l-amino acids to the as-prepared magnetic particles, and (ii) for targeted bio- and/or environmental applications where the surface chemistry needs to be tailored and directed toward biocompatible species. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
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Open AccessArticle Receptor-Targeted, Magneto-Mechanical Stimulation of Osteogenic Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells
Int. J. Mol. Sci. 2013, 14(9), 19276-19293; doi:10.3390/ijms140919276
Received: 6 August 2013 / Revised: 2 September 2013 / Accepted: 5 September 2013 / Published: 23 September 2013
Cited by 14 | PDF Full-text (2011 KB) | HTML Full-text | XML Full-text
Abstract
Mechanical cues are employed to promote stem cell differentiation and functional tissue formation in tissue engineering and regenerative medicine. We have developed a Magnetic Force Bioreactor (MFB) that delivers highly targeted local forces to cells at a pico-newton level, utilizing magnetic micro- and
[...] Read more.
Mechanical cues are employed to promote stem cell differentiation and functional tissue formation in tissue engineering and regenerative medicine. We have developed a Magnetic Force Bioreactor (MFB) that delivers highly targeted local forces to cells at a pico-newton level, utilizing magnetic micro- and nano-particles to target cell surface receptors. In this study, we investigated the effects of magnetically targeting and actuating specific two mechanical-sensitive cell membrane receptors—platelet-derived growth factor receptor α (PDGFRα) and integrin ανβ3. It was found that a higher mineral-to-matrix ratio was obtained after three weeks of magneto-mechanical stimulation coupled with osteogenic medium culture by initially targeting PDGFRα compared with targeting integrin ανβ3 and non-treated controls. Moreover, different initiation sites caused a differentiated response profile when using a 2-day-lagged magneto-mechanical stimulation over culture periods of 7 and 12 days). However, both resulted in statistically higher osteogenic marker genes expression compared with immediate magneto-mechanical stimulation. These results provide insights into important parameters for designing appropriate protocols for ex vivo induced bone formation via magneto-mechanical actuation. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessArticle Magnetic Nanosystem for Cancer Therapy Using Oncocalyxone A, an Antitomour Secondary Metabolite Isolated from a Brazilian Plant
Int. J. Mol. Sci. 2013, 14(9), 18269-18283; doi:10.3390/ijms140918269
Received: 13 April 2013 / Revised: 23 June 2013 / Accepted: 13 July 2013 / Published: 5 September 2013
Cited by 8 | PDF Full-text (1940 KB) | HTML Full-text | XML Full-text
Abstract
This paper describes the investigation and development of a novel magnetic drug delivery nanosystem (labeled as MO-20) for cancer therapy. The drug employed was oncocalyxone A (onco A), which was isolated from Auxemma oncocalyx, an endemic Brazilian plant. It has a series
[...] Read more.
This paper describes the investigation and development of a novel magnetic drug delivery nanosystem (labeled as MO-20) for cancer therapy. The drug employed was oncocalyxone A (onco A), which was isolated from Auxemma oncocalyx, an endemic Brazilian plant. It has a series of pharmacological properties: antioxidant, cytotoxic, analgesic, anti-inflammatory, antitumor and antiplatelet. Onco A was associated with magnetite nanoparticles in order to obtain magnetic properties. The components of MO-20 were characterized by XRD, FTIR, TGA, TEM and Magnetization curves. The MO-20 presented a size of about 30 nm and globular morphology. In addition, drug releasing experiments were performed, where it was observed the presence of the anomalous transport. The results found in this work showed the potential of onco A for future applications of the MO-20 as a new magnetic drug release nanosystem for cancer treatment. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessArticle Demagnetization Treatment of Remanent Composite Microspheres Studied by Alternating Current Susceptibility Measurements
Int. J. Mol. Sci. 2013, 14(9), 18093-18109; doi:10.3390/ijms140918093
Received: 3 July 2013 / Revised: 15 August 2013 / Accepted: 16 August 2013 / Published: 4 September 2013
Cited by 2 | PDF Full-text (800 KB) | HTML Full-text | XML Full-text
Abstract
The magnetic remanence of silica microspheres with a low concentration of embedded cobalt ferrite nanoparticles is studied after demagnetization and remagnetization treatments. When the microspheres are dispersed in a liquid, alternating current (AC) magnetic susceptibility spectra reveal a constant characteristic frequency, corresponding to
[...] Read more.
The magnetic remanence of silica microspheres with a low concentration of embedded cobalt ferrite nanoparticles is studied after demagnetization and remagnetization treatments. When the microspheres are dispersed in a liquid, alternating current (AC) magnetic susceptibility spectra reveal a constant characteristic frequency, corresponding to the rotational diffusion of the microparticles; this depends only on particle size and liquid viscosity, making the particles suitable as a rheological probe and indicating that interactions between the microspheres are weak. On the macroscopic scale, a sample with the dry microparticles is magnetically remanent after treatment in a saturating field, and after a demagnetization treatment, the remanence goes down to zero. The AC susceptibility of a liquid dispersion, however, characterizes the remanence on the scale of the individual microparticles, which does not become zero after demagnetization. The reason is that an individual microparticle contains only a relatively small number of magnetic units, so that even if they can be reoriented magnetically at random, the average vector sum of the nanoparticle dipoles is not negligible on the scale of the microparticle. In contrast, on the macroscopic scale, the demagnetization procedure randomizes the orientations of a macroscopic number of magnetic units, resulting in a remanent magnetization that is negligible compared to the saturation magnetization of the entire sample. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
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Open AccessArticle Biohybrid Nanostructured Iron Oxide Nanoparticles and Satureja hortensis to Prevent Fungal Biofilm Development
Int. J. Mol. Sci. 2013, 14(9), 18110-18123; doi:10.3390/ijms140918110
Received: 17 June 2013 / Revised: 5 August 2013 / Accepted: 23 August 2013 / Published: 4 September 2013
Cited by 25 | PDF Full-text (541 KB) | HTML Full-text | XML Full-text
Abstract
Cutaneous wounds are often superinfected during the healing process and this leads to prolonged convalescence and discomfort. Usage of suitable wound dressings is very important for an appropriate wound care leading to a correct healing. The aim of this study was to demonstrate
[...] Read more.
Cutaneous wounds are often superinfected during the healing process and this leads to prolonged convalescence and discomfort. Usage of suitable wound dressings is very important for an appropriate wound care leading to a correct healing. The aim of this study was to demonstrate the influence of a nano-coated wound dressing (WD) on Candida albicans colonization rate and biofilm formation. The modified WD was achieved by submerging the dressing pieces into a nanofluid composed of functionalized magnetite nanoparticles and Satureja hortensis (SO) essential oil (EO). Chemical composition of the EO was established by GC-MS. The fabricated nanostructure was characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Differential Thermal Analysis (DTA) and Fourier Transform-Infrared Spectroscopy (FT-IR). The analysis of the colonized surfaces using (Scanning Electron Microscopy) SEM revealed that C. albicans adherence and subsequent biofilm development are strongly inhibited on the surface of wound dressing fibers coated with the obtained nanofluid, comparing with regular uncoated materials. The results were also confirmed by the assay of the viable fungal cells embedded in the biofilm. Our data demonstrate that the obtained phytonanocoating improve the resistance of wound dressing surface to C. albicans colonization, which is often an etiological cause of local infections, impairing the appropriate wound healing. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessArticle Spin Polarization and Quantum Spins in Au Nanoparticles
Int. J. Mol. Sci. 2013, 14(9), 17618-17642; doi:10.3390/ijms140917618
Received: 4 July 2013 / Revised: 1 August 2013 / Accepted: 5 August 2013 / Published: 28 August 2013
Cited by 4 | PDF Full-text (793 KB) | HTML Full-text | XML Full-text
Abstract
The present study focuses on investigating the magnetic properties and the critical particle size for developing sizable spontaneous magnetic moment of bare Au nanoparticles. Seven sets of bare Au nanoparticle assemblies, with diameters from 3.5 to 17.5 nm, were fabricated with the gas
[...] Read more.
The present study focuses on investigating the magnetic properties and the critical particle size for developing sizable spontaneous magnetic moment of bare Au nanoparticles. Seven sets of bare Au nanoparticle assemblies, with diameters from 3.5 to 17.5 nm, were fabricated with the gas condensation method. Line profiles of the X-ray diffraction peaks were used to determine the mean particle diameters and size distributions of the nanoparticle assemblies. The magnetization curves M(Ha) reveal Langevin field profiles. Magnetic hysteresis was clearly revealed in the low field regime even at 300 K. Contributions to the magnetization from different size particles in the nanoparticle assemblies were considered when analyzing the M(Ha) curves. The results show that the maximum particle moment will appear in 2.4 nm Au particles. A similar result of the maximum saturation magnetization appearing in 2.3 nm Au particles is also concluded through analysis of the dependency of the saturation magnetization MP on particle size. The MP(d) curve departs significantly from the 1/d dependence, but can be described by a log-normal function. Magnetization can be barely detected for Au particles larger than 27 nm. Magnetic field induced Zeeman magnetization from the quantum confined Kubo gap opening appears in Au nanoparticles smaller than 9.5 nm in diameter. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
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Open AccessArticle Materials Characterization of Feraheme/Ferumoxytol and Preliminary Evaluation of Its Potential for Magnetic Fluid Hyperthermia
Int. J. Mol. Sci. 2013, 14(9), 17501-17510; doi:10.3390/ijms140917501
Received: 26 June 2013 / Revised: 5 August 2013 / Accepted: 21 August 2013 / Published: 26 August 2013
Cited by 11 | PDF Full-text (631 KB) | HTML Full-text | XML Full-text
Abstract
Feraheme, is a recently FDA-cleared superparamagnetic iron oxide nanoparticle (SPION)-based MRI contrast agent that is also employed in the treatment of iron deficiency anemia. Feraheme nanoparticles have a hydrodynamic diameter of 30 nm and consist of iron oxide crystallites complexed with a low
[...] Read more.
Feraheme, is a recently FDA-cleared superparamagnetic iron oxide nanoparticle (SPION)-based MRI contrast agent that is also employed in the treatment of iron deficiency anemia. Feraheme nanoparticles have a hydrodynamic diameter of 30 nm and consist of iron oxide crystallites complexed with a low molecular weight, semi-synthetic carbohydrate. These features are attractive for other potential biomedical applications such as magnetic fluid hyperthermia (MFH), since the carboxylated polymer coating affords functionalization of the particle surface and the size allows for accumulation in highly vascularized tumors via the enhanced permeability and retention effect. This work presents morphological and magnetic characterization of Feraheme by transmission electron microscopy (TEM), Energy dispersive X-ray spectroscopy (EDX), and superconducting quantum interference device (SQUID) magnetometry. Additionally, the results of an initial evaluation of the suitability of Feraheme for MFH applications are described, and the data indicate the particles possess promising properties for this application. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessArticle Effects of Fe3O4 Magnetic Nanoparticles on A549 Cells
Int. J. Mol. Sci. 2013, 14(8), 15546-15560; doi:10.3390/ijms140815546
Received: 8 June 2013 / Revised: 8 July 2013 / Accepted: 18 July 2013 / Published: 25 July 2013
Cited by 20 | PDF Full-text (1165 KB) | HTML Full-text | XML Full-text
Abstract
Fe3O4 magnetic nanoparticles (MgNPs-Fe3O4) are widely used in medical applications, including magnetic resonance imaging, drug delivery, and in hyperthermia. However, the same properties that aid their utility in the clinic may potentially induce toxicity. Therefore, the
[...] Read more.
Fe3O4 magnetic nanoparticles (MgNPs-Fe3O4) are widely used in medical applications, including magnetic resonance imaging, drug delivery, and in hyperthermia. However, the same properties that aid their utility in the clinic may potentially induce toxicity. Therefore, the purpose of this study was to investigate the cytotoxicity and genotoxicity of MgNPs-Fe3O4 in A549 human lung epithelial cells. MgNPs-Fe3O4 caused cell membrane damage, as assessed by the release of lactate dehydrogenase (LDH), only at a high concentration (100 μg/mL); a lower concentration (10 μg/mL) increased the production of reactive oxygen species, increased oxidative damage to DNA, and decreased the level of reduced glutathione. MgNPs-Fe3O4 caused a dose-dependent increase in the CD44+ fraction of A549 cells. MgNPs-Fe3O4 induced the expression of heme oxygenase-1 at a concentration of 1 μg/mL, and in a dose-dependent manner. Despite these effects, MgNPs-Fe3O4 had minimal effect on cell viability and elicited only a small increase in the number of cells undergoing apoptosis. Together, these data suggest that MgNPs-Fe3O4 exert little or no cytotoxicity until a high exposure level (100 μg/mL) is reached. This dissociation between elevated indices of cell damage and a small effect on cell viability warrants further study. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessArticle Chemical and Colloidal Stability of Carboxylated Core-Shell Magnetite Nanoparticles Designed for Biomedical Applications
Int. J. Mol. Sci. 2013, 14(7), 14550-14574; doi:10.3390/ijms140714550
Received: 2 May 2013 / Revised: 18 June 2013 / Accepted: 21 June 2013 / Published: 12 July 2013
Cited by 24 | PDF Full-text (2873 KB) | HTML Full-text | XML Full-text
Abstract
Despite the large efforts to prepare super paramagnetic iron oxide nanoparticles (MNPs) for biomedical applications, the number of FDA or EMA approved formulations is few. It is not known commonly that the approved formulations in many instances have already been withdrawn or discontinued
[...] Read more.
Despite the large efforts to prepare super paramagnetic iron oxide nanoparticles (MNPs) for biomedical applications, the number of FDA or EMA approved formulations is few. It is not known commonly that the approved formulations in many instances have already been withdrawn or discontinued by the producers; at present, hardly any approved formulations are produced and marketed. Literature survey reveals that there is a lack for a commonly accepted physicochemical practice in designing and qualifying formulations before they enter in vitro and in vivo biological testing. Such a standard procedure would exclude inadequate formulations from clinical trials thus improving their outcome. Here we present a straightforward route to assess eligibility of carboxylated MNPs for biomedical tests applied for a series of our core-shell products, i.e., citric acid, gallic acid, poly(acrylic acid) and poly(acrylic acid-co-maleic acid) coated MNPs. The discussion is based on physicochemical studies (carboxylate adsorption/desorption, FTIR-ATR, iron dissolution, zeta potential, particle size, coagulation kinetics and magnetization measurements) and involves in vitro and in vivo tests. Our procedure can serve as an example to construct adequate physico-chemical selection strategies for preparation of other types of core-shell nanoparticles as well. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
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Open AccessArticle Functional Expression of Thyroid-Stimulating Hormone Receptor on Nano-Sized Bacterial Magnetic Particles in Magnetospirillum magneticum AMB-1
Int. J. Mol. Sci. 2013, 14(7), 14426-14438; doi:10.3390/ijms140714426
Received: 2 April 2013 / Revised: 31 May 2013 / Accepted: 1 July 2013 / Published: 11 July 2013
Cited by 7 | PDF Full-text (251 KB) | HTML Full-text | XML Full-text
Abstract
The measurement of autoantibodies to thyroid-stimulating hormone receptor (TSHR) is important for the diagnosis of autoimmune thyroid disease such as Graves’ disease (GD). Although TSHR from porcine thyroid membrane is commonly used for the measurement of TSHR autoantibodies (TRAb), recombinant human TSHR (hTSHR)
[...] Read more.
The measurement of autoantibodies to thyroid-stimulating hormone receptor (TSHR) is important for the diagnosis of autoimmune thyroid disease such as Graves’ disease (GD). Although TSHR from porcine thyroid membrane is commonly used for the measurement of TSHR autoantibodies (TRAb), recombinant human TSHR (hTSHR) remains ideal in terms of stable supply and species identity. Here we set out to express recombinant hTSHR on the lipid-bilayer surface of magnetic nanoparticles from a magnetotactic bacterium, Magnetospirillum magneticum AMB-1. Using a tetracycline-inducible expression system, we successfully overexpressed functional hTSHR on bacterial magnetic particles (BacMPs) in AMB-1 via an anchor protein specific for BacMPs. The overexpressed hTSHR was membrane integrated and possessed both ligand and autoantibody binding activity. Our data suggest that hTSHR-displayed BacMPs have potential as novel tools for ligand-receptor interaction analysis or for TRAb immunoassay in GD patients. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
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Open AccessArticle Facile Synthesis of FeCo/Fe3O4 Nanocomposite with High Wave-Absorbing Properties
Int. J. Mol. Sci. 2013, 14(7), 14204-14213; doi:10.3390/ijms140714204
Received: 21 March 2013 / Revised: 20 June 2013 / Accepted: 21 June 2013 / Published: 9 July 2013
Cited by 6 | PDF Full-text (1143 KB) | HTML Full-text | XML Full-text
Abstract
The FeCo/Fe3O4 nanocomposite was synthesized using the hydrothermal approach, in which the FeCo alloy and Fe3O4 are formed by one step. The structure of the FeCo/Fe3O4 nanocomposite was characterized by means of Scanning electron
[...] Read more.
The FeCo/Fe3O4 nanocomposite was synthesized using the hydrothermal approach, in which the FeCo alloy and Fe3O4 are formed by one step. The structure of the FeCo/Fe3O4 nanocomposite was characterized by means of Scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray energy-dispersive spectrometer spectroscopy (EDX). They show that the mass ratio of FeCo/Fe3O4 strongly depends on the reaction temperature. Such various architectures follow a stepwise growth mechanism of the composites prepared in various reaction temperatures were also discussed. It indicates that this strategy is facile, effective and controllable for the synthesis of FeCo/Fe3O4 by the one-step method. Furthermore, the magnetic and wave-absorbing properties of the nanocomposites with various structures were investigated in detail. The results show that the FeCo/Fe3O4 with higher mass ratio has higher magnetic properties. Moreover, the FeCo/Fe3O4 nanocomposite shows high wave-absorbing properties (e.g., –37.9 dB), which are expected to apply in microwave absorbing materials. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessArticle Apoferritin Modified Magnetic Particles as Doxorubicin Carriers for Anticancer Drug Delivery
Int. J. Mol. Sci. 2013, 14(7), 13391-13402; doi:10.3390/ijms140713391
Received: 19 April 2013 / Revised: 18 May 2013 / Accepted: 23 May 2013 / Published: 27 June 2013
Cited by 15 | PDF Full-text (1865 KB) | HTML Full-text | XML Full-text
Abstract
Magnetic particle mediated transport in combination with nanomaterial based drug carrier has a great potential for targeted cancer therapy. In this study, doxorubicin encapsulation into the apoferritin and its conjugation with magnetic particles was investigated by capillary electrophoresis with laser-induced fluorescence detection (CE-LIF).
[...] Read more.
Magnetic particle mediated transport in combination with nanomaterial based drug carrier has a great potential for targeted cancer therapy. In this study, doxorubicin encapsulation into the apoferritin and its conjugation with magnetic particles was investigated by capillary electrophoresis with laser-induced fluorescence detection (CE-LIF). The quantification of encapsulated doxorubicin was performed by fluorescence spectroscopy and compared to CE-LIF. Moreover, the significant enhancement of the doxorubicin signal was observed by addition of methanol into the sample solution. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessArticle Preparation of Novel Poly(hydroxyethyl methacrylate-co-glycidyl methacrylate)-Grafted Core-Shell Magnetic Chitosan Microspheres and Immobilization of Lactase
Int. J. Mol. Sci. 2013, 14(6), 12073-12089; doi:10.3390/ijms140612073
Received: 6 April 2013 / Revised: 19 May 2013 / Accepted: 31 May 2013 / Published: 6 June 2013
Cited by 5 | PDF Full-text (985 KB) | HTML Full-text | XML Full-text
Abstract
Poly(hydroxyethyl methacrylate-co-glycidyl methacrylate)-grafted magnetic chitosan microspheres (HG-MCM) were prepared using reversed-phase suspension polymerization method. The HG-MCM presented a core-shell structure and regular spherical shape with poly(hydroxyethyl methacrylate-co-glycidyl methacrylate) grafted onto the chitosan layer coating the Fe3O4
[...] Read more.
Poly(hydroxyethyl methacrylate-co-glycidyl methacrylate)-grafted magnetic chitosan microspheres (HG-MCM) were prepared using reversed-phase suspension polymerization method. The HG-MCM presented a core-shell structure and regular spherical shape with poly(hydroxyethyl methacrylate-co-glycidyl methacrylate) grafted onto the chitosan layer coating the Fe3O4 cores. The average diameter of the magnetic microspheres was 10.67 μm, within a narrow size distribution of 6.6–17.4 μm. The saturation magnetization and retentivity of the magnetic microspheres were 7.0033 emu/g and 0.6273 emu/g, respectively. The application of HG-MCM in immobilization of lactase showed that the immobilized enzyme presented higher storage, pH and thermal stability compared to the free enzyme. This indicates that HG-MCM have potential applications in bio-macromolecule immobilization. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessArticle Optimization of Synthesis Parameters for Mesoporous Shell Formation on Magnetic Nanocores and Their Application as Nanocarriers for Docetaxel Cancer Drug
Int. J. Mol. Sci. 2013, 14(6), 11496-11509; doi:10.3390/ijms140611496
Received: 16 February 2013 / Revised: 3 May 2013 / Accepted: 15 May 2013 / Published: 30 May 2013
Cited by 9 | PDF Full-text (1183 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
In this work, Fe3O4@SiO2 nanoparticles were coated with mesoporous silica shell by SN+I pathway by using anionic surfactant (S) and co-structure directing agent (N+). The role of co-structure directing
[...] Read more.
In this work, Fe3O4@SiO2 nanoparticles were coated with mesoporous silica shell by SN+I pathway by using anionic surfactant (S) and co-structure directing agent (N+). The role of co-structure directing agent (CSDA) is to assist the electrostatic interaction between negatively charged silica layers and the negatively charged surfactant molecules. Prior to the mesoporous shell formation step, magnetic cores were coated with a dense silica layer to prevent iron oxide cores from leaching into the mother system under any acidic circumstances. However, it was found that both dense and mesoporous coating parameters affect the textural properties of the produced mesoporous silica shell (i.e., surface area, pore volume and shell thickness). The synthesized Fe3O4@SiO2@m-SiO2 (MCMSS) nanoparticles have been characterized by low-angle X-ray diffraction, transmission electron microscopy (TEM), and N2 adsorption-desorption analysis, and magnetic properties. The synthesized particles had dense and mesoporous silica shells of 8–37 nm and 26–50 nm, respectively. Furthermore, MCMSS possessed surface area of ca. 259–621 m2·g1, and pore volume of ca. 0.216–0.443 cc·g1. MCMSS showed docetaxcel cancer drug storage capacity of 25–33 w/w% and possessed control release from their mesochannels which suggest them as proper nanocarriers for docetaxcel molecules. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessArticle Generation of Magnetized Olfactory Ensheathing Cells for Regenerative Studies in the Central and Peripheral Nervous Tissue
Int. J. Mol. Sci. 2013, 14(6), 10852-10868; doi:10.3390/ijms140610852
Received: 1 April 2013 / Revised: 8 May 2013 / Accepted: 13 May 2013 / Published: 24 May 2013
Cited by 6 | PDF Full-text (2208 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
As olfactory receptor axons grow from the peripheral to the central nervous system (CNS) aided by olfactory ensheathing cells (OECs), the transplantation of OECs has been suggested as a plausible therapy for spinal cord lesions. The problem with this hypothesis is that OECs
[...] Read more.
As olfactory receptor axons grow from the peripheral to the central nervous system (CNS) aided by olfactory ensheathing cells (OECs), the transplantation of OECs has been suggested as a plausible therapy for spinal cord lesions. The problem with this hypothesis is that OECs do not represent a single homogeneous entity, but, instead, a functionally heterogeneous population that exhibits a variety of responses, including adhesion and repulsion during cell-matrix interactions. Some studies report that the migratory properties of OECs are compromised by inhibitory molecules and potentiated by chemical gradients. In this paper, we report a system based on modified OECs carrying magnetic nanoparticles as a proof of concept experiment enabling specific studies aimed at exploring the potential of OECs in the treatment of spinal cord injuries. Our studies have confirmed that magnetized OECs (i) survive well without exhibiting stress-associated cellular responses; (ii) in vitro, their migration can be modulated by magnetic fields; and (iii) their transplantation in organotypic slices of spinal cord and peripheral nerve showed positive integration in the model. Altogether, these findings indicate the therapeutic potential of magnetized OECs for CNS injuries. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
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Open AccessArticle Innovative Strategy for MicroRNA Delivery in Human Mesenchymal Stem Cells via Magnetic Nanoparticles
Int. J. Mol. Sci. 2013, 14(6), 10710-10726; doi:10.3390/ijms140610710
Received: 27 March 2013 / Revised: 29 April 2013 / Accepted: 3 May 2013 / Published: 23 May 2013
Cited by 18 | PDF Full-text (2634 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Bone marrow derived human mesenchymal stem cells (hMSCs) show promising potential in regeneration of defective tissue. Recently, gene silencing strategies using microRNAs (miR) emerged with the aim to expand the therapeutic potential of hMSCs. However, researchers are still searching for effective miR delivery
[...] Read more.
Bone marrow derived human mesenchymal stem cells (hMSCs) show promising potential in regeneration of defective tissue. Recently, gene silencing strategies using microRNAs (miR) emerged with the aim to expand the therapeutic potential of hMSCs. However, researchers are still searching for effective miR delivery methods for clinical applications. Therefore, we aimed to develop a technique to efficiently deliver miR into hMSCs with the help of a magnetic non-viral vector based on cationic polymer polyethylenimine (PEI) bound to iron oxide magnetic nanoparticles (MNP). We tested different magnetic complex compositions and determined uptake efficiency and cytotoxicity by flow cytometry. Additionally, we monitored the release, processing and functionality of delivered miR-335 with confocal laser scanning microscopy, real-time PCR and live cell imaging, respectively. On this basis, we established parameters for construction of magnetic non-viral vectors with optimized uptake efficiency (~75%) and moderate cytotoxicity in hMSCs. Furthermore, we observed a better transfection performance of magnetic complexes compared to PEI complexes 72 h after transfection. We conclude that MNP-mediated transfection provides a long term effect beneficial for successful genetic modification of stem cells. Hence, our findings may become of great importance for future in vivo applications. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessArticle Influence of Growth Conditions on Magnetite Nanoparticles Electro-Crystallized in the Presence of Organic Molecules
Int. J. Mol. Sci. 2013, 14(5), 10383-10396; doi:10.3390/ijms140510383
Received: 29 March 2013 / Revised: 4 May 2013 / Accepted: 9 May 2013 / Published: 17 May 2013
Cited by 8 | PDF Full-text (1503 KB) | HTML Full-text | XML Full-text
Abstract
Magnetite nanoparticles were synthesized by electrocrystallization in the presence of thiourea or sodium butanoate as an organic stabilizer. The synthesis was performed in a thermostatic electrochemical cell containing two iron electrodes with an aqueous solution of sodium sulfate as electrolyte. The effects of
[...] Read more.
Magnetite nanoparticles were synthesized by electrocrystallization in the presence of thiourea or sodium butanoate as an organic stabilizer. The synthesis was performed in a thermostatic electrochemical cell containing two iron electrodes with an aqueous solution of sodium sulfate as electrolyte. The effects of organic concentration, applied potential and growth temperature on particle size, morphology, structure and magnetic properties were investigated. The magnetite nanoparticles were characterized by X-ray diffraction, electron microscopy, magnetometry and Mössbauer spectrometry. When the synthesis is performed in the presence of sodium butanoate at 60 °C, a paramagnetic ferric salt is obtained as a second phase; it is possible to avoid formation of this phase, increase the specific magnetization and improve the structure of the oxide particles by tuning the growth conditions. Room-temperature magnetization values range from 45 to 90 Am2kg−1, depending on the particle size, type of surfactant and synthesis conditions. Mössbauer spectra, which were recorded at 290 K for all the samples, are typical of nonstoichiometric Fe3−δO4, with a small excess of Fe3+, 0.05 ≤ δ ≤ 0.15. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
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Open AccessArticle Frequency-Dependent Magnetic Susceptibility of Magnetite and Cobalt Ferrite Nanoparticles Embedded in PAA Hydrogel
Int. J. Mol. Sci. 2013, 14(5), 10162-10177; doi:10.3390/ijms140510162
Received: 11 April 2013 / Revised: 29 April 2013 / Accepted: 7 May 2013 / Published: 14 May 2013
Cited by 11 | PDF Full-text (1764 KB) | HTML Full-text | XML Full-text
Abstract
Chemically responsive hydrogels with embedded magnetic nanoparticles are of interest for biosensors that magnetically detect chemical changes. A crucial point is the irreversible linkage of nanoparticles to the hydrogel network, preventing loss of nanoparticles upon repeated swelling and shrinking of the gel. Here,
[...] Read more.
Chemically responsive hydrogels with embedded magnetic nanoparticles are of interest for biosensors that magnetically detect chemical changes. A crucial point is the irreversible linkage of nanoparticles to the hydrogel network, preventing loss of nanoparticles upon repeated swelling and shrinking of the gel. Here, acrylic acid monomers are adsorbed onto ferrite nanoparticles, which subsequently participate in polymerization during synthesis of poly(acrylic acid)-based hydrogels (PAA). To demonstrate the fixation of the nanoparticles to the polymer, our original approach is to measure low-field AC magnetic susceptibility spectra in the 0.1 Hz to 1 MHz range. In the hydrogel, the magnetization dynamics of small iron oxide nanoparticles are comparable to those of the particles dispersed in a liquid, due to fast Néel relaxation inside the particles; this renders the ferrogel useful for chemical sensing at frequencies of several kHz. However, ferrogels holding thermally blocked iron oxide or cobalt ferrite nanoparticles show significant decrease of the magnetic susceptibility resulting from a frozen magnetic structure. This confirms that the nanoparticles are unable to rotate thermally inside the hydrogel, in agreement with their irreversible fixation to the polymer network. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
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Open AccessArticle A Novel Colorimetric Immunoassay Utilizing the Peroxidase Mimicking Activity of Magnetic Nanoparticles
Int. J. Mol. Sci. 2013, 14(5), 9999-10014; doi:10.3390/ijms14059999
Received: 7 April 2013 / Revised: 28 April 2013 / Accepted: 6 May 2013 / Published: 10 May 2013
Cited by 10 | PDF Full-text (896 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A simple colorimetric immunoassay system, based on the peroxidase mimicking activity of Fe3O4 magnetic nanoparticles (MNPs), has been developed to detect clinically important antigenic molecules. MNPs with ca. 10 nm in diameter were synthesized and conjugated with specific antibodies against
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A simple colorimetric immunoassay system, based on the peroxidase mimicking activity of Fe3O4 magnetic nanoparticles (MNPs), has been developed to detect clinically important antigenic molecules. MNPs with ca. 10 nm in diameter were synthesized and conjugated with specific antibodies against target molecules, such as rotaviruses and breast cancer cells. Conjugation of the MNPs with antibodies (MNP-Abs) enabled specific recognition of the corresponding target antigenic molecules through the generation of color signals arising from the colorimetric reaction between the selected peroxidase substrate, 3,3',5,5'-tetramethylbenzidine (TMB) and H2O2. Based on the MNP-promoted colorimetric reaction, the target molecules were detected and quantified by measuring absorbance intensities corresponding to the oxidized form of TMB. Owing to the higher stabilities and economic feasibilities of MNPs as compared to horseradish peroxidase (HRP), the new colorimetric system employing MNP-Abs has the potential of serving as a potent immunoassay that should substitute for conventional HRP-based immunoassays. The strategy employed to develop the new methodology has the potential of being extended to the construction of simple diagnostic systems for a variety of biomolecules related to human cancers and infectious diseases, particularly in the realm of point-of-care applications. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
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Open AccessArticle Effective and Selective Recovery of Precious Metals by Thiourea Modified Magnetic Nanoparticles
Int. J. Mol. Sci. 2013, 14(5), 9834-9847; doi:10.3390/ijms14059834
Received: 1 April 2013 / Revised: 26 April 2013 / Accepted: 3 May 2013 / Published: 8 May 2013
Cited by 6 | PDF Full-text (447 KB) | HTML Full-text | XML Full-text
Abstract
Adsorption of precious metals in acidic aqueous solutions using thiourea modified magnetic magnetite nanoparticle (MNP-Tu) was examined. The MNP-Tu was synthesized, characterized and examined as a reusable adsorbent for the recovery of precious metals. The adsorption kinetics were well fitted with pseudo second-order
[...] Read more.
Adsorption of precious metals in acidic aqueous solutions using thiourea modified magnetic magnetite nanoparticle (MNP-Tu) was examined. The MNP-Tu was synthesized, characterized and examined as a reusable adsorbent for the recovery of precious metals. The adsorption kinetics were well fitted with pseudo second-order equation while the adsorption isotherms were fitted with both Langmuir and Freundlich equations. The maximum adsorption capacity of precious metals for MNP-Tu determined by Langmuir model was 43.34, 118.46 and 111.58 mg/g for Pt(IV), Au(III) and Pd(II), respectively at pH 2 and 25 °C. MNP-Tu has high adsorption selectivity towards precious metals even in the presence of competing ions (Cu(II)) at high concentrations. In addition, the MNP-Tu can be regenerated using an aqueous solution containing 0.7 M thiourea and 2% HCl where precious metals can be recovered in a concentrated form. It was found that the MNP-Tu undergoing seven consecutive adsorption-desorption cycles still retained the original adsorption capacity of precious metals. A reductive adsorption resulting in the formation of elemental gold and palladium at the surface of MNP-Tu was observed. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessArticle Simple and Rapid Synthesis of Magnetite/Hydroxyapatite Composites for Hyperthermia Treatments via a Mechanochemical Route
Int. J. Mol. Sci. 2013, 14(5), 9365-9378; doi:10.3390/ijms14059365
Received: 22 February 2013 / Revised: 19 April 2013 / Accepted: 22 April 2013 / Published: 29 April 2013
Cited by 18 | PDF Full-text (1897 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents a simple method for the rapid synthesis of magnetite/hydroxyapatite composite particles. In this method, superparamagnetic magnetite nanoparticles are first synthesized by coprecipitation using ferrous chloride and ferric chloride. Immediately following the synthesis, carbonate-substituted (B-type) hydroxyapatite particles are mechanochemically synthesized by
[...] Read more.
This paper presents a simple method for the rapid synthesis of magnetite/hydroxyapatite composite particles. In this method, superparamagnetic magnetite nanoparticles are first synthesized by coprecipitation using ferrous chloride and ferric chloride. Immediately following the synthesis, carbonate-substituted (B-type) hydroxyapatite particles are mechanochemically synthesized by wet milling dicalcium phosphate dihydrate and calcium carbonate in a dispersed suspension of magnetite nanoparticles, during which the magnetite nanoparticles are incorporated into the hydroxyapatite matrix. We observed that the resultant magnetite/hydroxyapatite composites possessed a homogeneous dispersion of magnetite nanoparticles, characterized by an absence of large aggregates. When this material was subjected to an alternating magnetic field, the heat generated increased with increasing magnetite concentration. For a magnetite concentration of 30 mass%, a temperature increase greater than 20 K was achieved in less than 50 s. These results suggest that our composites exhibit good hyperthermia properties and are promising candidates for hyperthermia treatments. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessArticle Tumour Cell Labelling by Magnetic Nanoparticles with Determination of Intracellular Iron Content and Spatial Distribution of the Intracellular Iron
Int. J. Mol. Sci. 2013, 14(5), 9111-9125; doi:10.3390/ijms14059111
Received: 1 March 2013 / Revised: 26 March 2013 / Accepted: 2 April 2013 / Published: 26 April 2013
Cited by 18 | PDF Full-text (488 KB) | HTML Full-text | XML Full-text
Abstract
Magnetically labelled cells are used for in vivo cell tracking by MRI, used for the clinical translation of cell-base therapies. Studies involving magnetic labelled cells may include separation of labelled cells, targeted delivery and controlled release of drugs, contrast enhanced MRI and magnetic
[...] Read more.
Magnetically labelled cells are used for in vivo cell tracking by MRI, used for the clinical translation of cell-base therapies. Studies involving magnetic labelled cells may include separation of labelled cells, targeted delivery and controlled release of drugs, contrast enhanced MRI and magnetic hyperthermia for the in situ ablation of tumours. Dextran-coated super-paramagnetic iron oxide (SPIO) ferumoxides are used clinically as an MR contrast agents primarily for hepatic imaging. The material is also widely used for in vitro cell labelling, as are other SPIO-based particles. Our results on the uptake by human cancer cell lines of ferumoxides indicate that electroporation in the presence of protamine sulphate (PS) results in rapid high uptake of SPIO nanoparticles (SPIONs) by parenchymal tumour cells without significant impairment of cell viability. Quantitative determination of cellular iron uptake performed by colorimetric assay is in agreement with data from the literature. These results on intracellular iron content together with the intracellular distribution of SPIONs by magnetic force microscopy (MFM) following in vitro uptake by parenchymal tumour cells confirm the potential of this technique for clinical tumour cell detection and destruction. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessArticle A One-Step Homogeneous Sandwich Immunosensor for Salmonella Detection Based on Magnetic Nanoparticles (MNPs) and Quantum Dots (QDs)
Int. J. Mol. Sci. 2013, 14(4), 8603-8610; doi:10.3390/ijms14048603
Received: 6 February 2013 / Revised: 15 April 2013 / Accepted: 16 April 2013 / Published: 22 April 2013
Cited by 20 | PDF Full-text (152 KB) | HTML Full-text | XML Full-text
Abstract
Simple immuno-magnetic separation tandem fluorescent probes based on quantum dots-antibody (QDs-Ab) were developed to detect Salmonella with sensitivity of 500 cfu mL−1. With two monoclonal antibodies, which recognize different antigenic determinant on the surface of Salmonella, we prepared antibody-coated magnetic
[...] Read more.
Simple immuno-magnetic separation tandem fluorescent probes based on quantum dots-antibody (QDs-Ab) were developed to detect Salmonella with sensitivity of 500 cfu mL−1. With two monoclonal antibodies, which recognize different antigenic determinant on the surface of Salmonella, we prepared antibody-coated magnetic nanoparticles (MNPs) and conjugates of QDs-Ab. The immune-magnetic beads were verified with high enrichment efficiency for Salmonella (90%). A sandwich structure formed if the Salmonella solution was mixed together with immune-beads and QDs-Ab, and the fluorescent single from QDs was related to the amount of Salmonella. A linear response between fluorescence intensity and various concentrations of Salmonella (2.5 × 103 to 1.95 × 108 cfu mL−1) were observed with this proposed method. The total assay time for Salmonella was 30 min, and no cross-reaction to other microbial strains, such as Staphylococcus aureus, Escherichia coli (E. coli) and Escherichia coli O157:H7 (E. coli O157:H7), were found using this detection system. All our results showed that the simple homogeneous immunoassay could be applied in Salmonella screening without time-consuming extra-enrichment of bacteria. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessArticle Remotely Triggered Scaffolds for Controlled Release of Pharmaceuticals
Int. J. Mol. Sci. 2013, 14(4), 8585-8602; doi:10.3390/ijms14048585
Received: 20 March 2013 / Revised: 12 April 2013 / Accepted: 16 April 2013 / Published: 19 April 2013
Cited by 9 | PDF Full-text (1198 KB) | HTML Full-text | XML Full-text
Abstract
Fe3O4-Au hybrid nanoparticles (HNPs) have shown increasing potential for biomedical applications such as image guided stimuli responsive drug delivery. Incorporation of the unique properties of HNPs into thermally responsive scaffolds holds great potential for future biomedical applications. Here we
[...] Read more.
Fe3O4-Au hybrid nanoparticles (HNPs) have shown increasing potential for biomedical applications such as image guided stimuli responsive drug delivery. Incorporation of the unique properties of HNPs into thermally responsive scaffolds holds great potential for future biomedical applications. Here we successfully fabricated smart scaffolds based on thermo-responsive poly(N-isopropylacrylamide) (pNiPAM). Nanoparticles providing localized trigger of heating when irradiated with a short laser burst were found to give rise to remote control of bulk polymer shrinkage. Gold-coated iron oxide nanoparticles were synthesized using wet chemical precipitation methods followed by electrochemical coating. After subsequent functionalization of particles with allyl methyl sulfide, mercaptodecane, cysteamine and poly(ethylene glycol) thiol to enhance stability, detailed biological safety was determined using live/dead staining and cell membrane integrity studies through lactate dehydrogenase (LDH) quantification. The PEG coated HNPs did not show significant cytotoxic effect or adverse cellular response on exposure to 7F2 cells (p < 0.05) and were carried forward for scaffold incorporation. The pNiPAM-HNP composite scaffolds were investigated for their potential as thermally triggered systems using a Q-switched Nd:YAG laser. These studies show that incorporation of HNPs resulted in scaffold deformation after very short irradiation times (seconds) due to internal structural heating. Our data highlights the potential of these hybrid-scaffold constructs for exploitation in drug delivery, using methylene blue as a model drug being released during remote structural change of the scaffold. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessArticle Gold-Coated Iron Composite Nanospheres Targeted the Detection of Escherichia coli
Int. J. Mol. Sci. 2013, 14(3), 6223-6240; doi:10.3390/ijms14036223
Received: 28 November 2012 / Revised: 28 February 2013 / Accepted: 28 February 2013 / Published: 18 March 2013
Cited by 14 | PDF Full-text (3443 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
We report the preparation and characterization of spherical core-shell structured Fe3O4–Au magnetic nanoparticles, modified with two component self-assembled monolayers (SAMs) consisting of 3–mercaptophenylboronic acid (3–MBA) and 1–decanethiol (1–DT). The rapid and room temperature synthesis of magnetic nanoparticles was achieved
[...] Read more.
We report the preparation and characterization of spherical core-shell structured Fe3O4–Au magnetic nanoparticles, modified with two component self-assembled monolayers (SAMs) consisting of 3–mercaptophenylboronic acid (3–MBA) and 1–decanethiol (1–DT). The rapid and room temperature synthesis of magnetic nanoparticles was achieved using the hydroxylamine reduction of HAuCl4 on the surface of ethylenediaminetetraacetic acid (EDTA)-immobilized iron (magnetite Fe3O4) nanoparticles in the presence of an aqueous solution of hexadecyltrimetylammonium bromide (CTAB) as a dispersant. The reduction of gold on the surface of Fe3O4 nanoparticles exhibits a uniform, highly stable, and narrow particle size distribution of Fe3O4–Au nanoparticles with an average diameter of 9 ± 2 nm. The saturation magnetization value for the resulting nanoparticles was found to be 15 emu/g at 298 K. Subsequent surface modification with SAMs against glucoside moieties on the surface of bacteria provided effective magnetic separation. Comparison of the bacteria capturing efficiency, by means of different molecular recognition agents 3–MBA, 1–DT and the mixed monolayer of 3–MBA and 1–DT was presented. The best capturing efficiency of E. coli was achieved with the mixed monolayer of 3–MBA and 1–DT-modified nanoparticles. Molecular specificity and selectivity were also demonstrated by comparing the surface-enhanced Raman scattering (SERS) spectrum of E. coli-nanoparticle conjugates with bacterial growth media. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessArticle Covalent Immobilization of Bacillus licheniformis γ-Glutamyl Transpeptidase on Aldehyde-Functionalized Magnetic Nanoparticles
Int. J. Mol. Sci. 2013, 14(3), 4613-4628; doi:10.3390/ijms14034613
Received: 15 January 2013 / Revised: 20 February 2013 / Accepted: 21 February 2013 / Published: 26 February 2013
Cited by 13 | PDF Full-text (1738 KB) | HTML Full-text | XML Full-text
Abstract
This work presents the synthesis and use of surface-modified iron oxide nanoparticles for the covalent immobilization of Bacillus licheniformis γ-glutamyl transpeptidase (BlGGT). Magnetic nanoparticles were prepared by an alkaline solution of divalent and trivalent iron ions, and they were subsequently treated
[...] Read more.
This work presents the synthesis and use of surface-modified iron oxide nanoparticles for the covalent immobilization of Bacillus licheniformis γ-glutamyl transpeptidase (BlGGT). Magnetic nanoparticles were prepared by an alkaline solution of divalent and trivalent iron ions, and they were subsequently treated with 3-aminopropyltriethoxysilane (APES) to obtain the aminosilane-coated nanoparticles. The functional group on the particle surface and the amino group of BlGGT was then cross-linked using glutaraldehyde as the coupling reagent. The loading capacity of the prepared nanoparticles for BlGGT was 34.2 mg/g support, corresponding to 52.4% recovery of the initial activity. Monographs of transmission electron microscopy revealed that the synthesized nanoparticles had a mean diameter of 15.1 ± 3.7 nm, and the covalent cross-linking of the enzyme did not significantly change their particle size. Fourier transform infrared spectroscopy confirmed the immobilization of BlGGT on the magnetic nanoparticles. The chemical and kinetic behaviors of immobilized BlGGT are mostly consistent with those of the free enzyme. The immobilized enzyme could be recycled ten times with 36.2% retention of the initial activity and had a comparable stability respective to free enzyme during the storage period of 30 days. Collectively, the straightforward synthesis of aldehyde-functionalized nanoparticles and the efficiency of enzyme immobilization offer wide perspectives for the practical use of surface-bound BlGGT. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)

Review

Jump to: Research

Open AccessReview Magnetic Nanoparticles: Surface Effects and Properties Related to Biomedicine Applications
Int. J. Mol. Sci. 2013, 14(11), 21266-21305; doi:10.3390/ijms141121266
Received: 2 August 2013 / Revised: 10 October 2013 / Accepted: 11 October 2013 / Published: 25 October 2013
Cited by 110 | PDF Full-text (1105 KB) | HTML Full-text | XML Full-text
Abstract
Due to finite size effects, such as the high surface-to-volume ratio and different crystal structures, magnetic nanoparticles are found to exhibit interesting and considerably different magnetic properties than those found in their corresponding bulk materials. These nanoparticles can be synthesized in several ways
[...] Read more.
Due to finite size effects, such as the high surface-to-volume ratio and different crystal structures, magnetic nanoparticles are found to exhibit interesting and considerably different magnetic properties than those found in their corresponding bulk materials. These nanoparticles can be synthesized in several ways (e.g., chemical and physical) with controllable sizes enabling their comparison to biological organisms from cells (10–100 μm), viruses, genes, down to proteins (3–50 nm). The optimization of the nanoparticles’ size, size distribution, agglomeration, coating, and shapes along with their unique magnetic properties prompted the application of nanoparticles of this type in diverse fields. Biomedicine is one of these fields where intensive research is currently being conducted. In this review, we will discuss the magnetic properties of nanoparticles which are directly related to their applications in biomedicine. We will focus mainly on surface effects and ferrite nanoparticles, and on one diagnostic application of magnetic nanoparticles as magnetic resonance imaging contrast agents. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessReview Design of Superparamagnetic Nanoparticles for Magnetic Particle Imaging (MPI)
Int. J. Mol. Sci. 2013, 14(9), 18682-18710; doi:10.3390/ijms140918682
Received: 15 July 2013 / Revised: 29 July 2013 / Accepted: 14 August 2013 / Published: 11 September 2013
Cited by 7 | PDF Full-text (10255 KB) | HTML Full-text | XML Full-text
Abstract
Magnetic particle imaging (MPI) is a promising medical imaging technique producing quantitative images of the distribution of tracer materials (superparamagnetic nanoparticles) without interference from the anatomical background of the imaging objects (either phantoms or lab animals). Theoretically, the MPI platform can image with
[...] Read more.
Magnetic particle imaging (MPI) is a promising medical imaging technique producing quantitative images of the distribution of tracer materials (superparamagnetic nanoparticles) without interference from the anatomical background of the imaging objects (either phantoms or lab animals). Theoretically, the MPI platform can image with relatively high temporal and spatial resolution and sensitivity. In practice, the quality of the MPI images hinges on both the applied magnetic field and the properties of the tracer nanoparticles. Langevin theory can model the performance of superparamagnetic nanoparticles and predict the crucial influence of nanoparticle core size on the MPI signal. In addition, the core size distribution, anisotropy of the magnetic core and surface modification of the superparamagnetic nanoparticles also determine the spatial resolution and sensitivity of the MPI images. As a result, through rational design of superparamagnetic nanoparticles, the performance of MPI could be effectively optimized. In this review, the performance of superparamagnetic nanoparticles in MPI is investigated. Rational synthesis and modification of superparamagnetic nanoparticles are discussed and summarized. The potential medical application areas for MPI, including cardiovascular system, oncology, stem cell tracking and immune related imaging are also analyzed and forecasted. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
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Open AccessReview Microfluidic Biosensing Systems Using Magnetic Nanoparticles
Int. J. Mol. Sci. 2013, 14(9), 18535-18556; doi:10.3390/ijms140918535
Received: 21 June 2013 / Revised: 7 August 2013 / Accepted: 21 August 2013 / Published: 9 September 2013
Cited by 16 | PDF Full-text (881 KB) | HTML Full-text | XML Full-text
Abstract
In recent years, there has been rapidly growing interest in developing hand held, sensitive and cost-effective on-chip biosensing systems that directly translate the presence of certain bioanalytes (e.g., biomolecules, cells and viruses) into an electronic signal. The impressive and rapid progress in micro-
[...] Read more.
In recent years, there has been rapidly growing interest in developing hand held, sensitive and cost-effective on-chip biosensing systems that directly translate the presence of certain bioanalytes (e.g., biomolecules, cells and viruses) into an electronic signal. The impressive and rapid progress in micro- and nanotechnology as well as in biotechnology enables the integration of a variety of analytical functions in a single chip. All necessary sample handling and analysis steps are then performed within the chip. Microfluidic systems for biomedical analysis usually consist of a set of units, which guarantees the manipulation, detection and recognition of bioanalytes in a reliable and flexible manner. Additionally, the use of magnetic fields for performing the aforementioned tasks has been steadily gaining interest. This is because magnetic fields can be well tuned and applied either externally or from a directly integrated solution in the biosensing system. In combination with these applied magnetic fields, magnetic nanoparticles are utilized. Some of the merits of magnetic nanoparticles are the possibility of manipulating them inside microfluidic channels by utilizing high gradient magnetic fields, their detection by integrated magnetic microsensors, and their flexibility due to functionalization by means of surface modification and specific binding. Their multi-functionality is what makes them ideal candidates as the active component in miniaturized on-chip biosensing systems. In this review, focus will be given to the type of biosening systems that use microfluidics in combination with magnetoresistive sensors and detect the presence of bioanalyte tagged with magnetic nanoparticles. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessReview Magnetic Iron Oxide Nanoparticles for Multimodal Imaging and Therapy of Cancer
Int. J. Mol. Sci. 2013, 14(8), 15910-15930; doi:10.3390/ijms140815910
Received: 23 May 2013 / Revised: 16 July 2013 / Accepted: 18 July 2013 / Published: 31 July 2013
Cited by 60 | PDF Full-text (2398 KB) | HTML Full-text | XML Full-text
Abstract
Superparamagnetic iron oxide nanoparticles (SPION) have emerged as an MRI contrast agent for tumor imaging due to their efficacy and safety. Their utility has been proven in clinical applications with a series of marketed SPION-based contrast agents. Extensive research has been performed to
[...] Read more.
Superparamagnetic iron oxide nanoparticles (SPION) have emerged as an MRI contrast agent for tumor imaging due to their efficacy and safety. Their utility has been proven in clinical applications with a series of marketed SPION-based contrast agents. Extensive research has been performed to study various strategies that could improve SPION by tailoring the surface chemistry and by applying additional therapeutic functionality. Research into the dual-modal contrast uses of SPION has developed because these applications can save time and effort by reducing the number of imaging sessions. In addition to multimodal strategies, efforts have been made to develop multifunctional nanoparticles that carry both diagnostic and therapeutic cargos specifically for cancer. This review provides an overview of recent advances in multimodality imaging agents and focuses on iron oxide based nanoparticles and their theranostic applications for cancer. Furthermore, we discuss the physiochemical properties and compare different synthesis methods of SPION for the development of multimodal contrast agents. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessReview Tuning the Magnetic Properties of Nanoparticles
Int. J. Mol. Sci. 2013, 14(8), 15977-16009; doi:10.3390/ijms140815977
Received: 13 May 2013 / Revised: 22 June 2013 / Accepted: 15 July 2013 / Published: 31 July 2013
Cited by 79 | PDF Full-text (642 KB) | HTML Full-text | XML Full-text
Abstract
The tremendous interest in magnetic nanoparticles (MNPs) is reflected in published research that ranges from novel methods of synthesis of unique nanoparticle shapes and composite structures to a large number of MNP characterization techniques, and finally to their use in many biomedical and
[...] Read more.
The tremendous interest in magnetic nanoparticles (MNPs) is reflected in published research that ranges from novel methods of synthesis of unique nanoparticle shapes and composite structures to a large number of MNP characterization techniques, and finally to their use in many biomedical and nanotechnology-based applications. The knowledge gained from this vast body of research can be made more useful if we organize the associated results to correlate key magnetic properties with the parameters that influence them. Tuning these properties of MNPs will allow us to tailor nanoparticles for specific applications, thus increasing their effectiveness. The complex magnetic behavior exhibited by MNPs is governed by many factors; these factors can either improve or adversely affect the desired magnetic properties. In this report, we have outlined a matrix of parameters that can be varied to tune the magnetic properties of nanoparticles. For practical utility, this review focuses on the effect of size, shape, composition, and shell-core structure on saturation magnetization, coercivity, blocking temperature, and relaxation time. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
Open AccessReview Nanoparticle-Based Systems for T1-Weighted Magnetic Resonance Imaging Contrast Agents
Int. J. Mol. Sci. 2013, 14(5), 10591-10607; doi:10.3390/ijms140510591
Received: 18 March 2013 / Revised: 9 May 2013 / Accepted: 13 May 2013 / Published: 21 May 2013
Cited by 28 | PDF Full-text (1565 KB) | HTML Full-text | XML Full-text
Abstract
Because magnetic resonance imaging (MRI) contrast agents play a vital role in diagnosing diseases, demand for new MRI contrast agents, with an enhanced sensitivity and advanced functionalities, is very high. During the past decade, various inorganic nanoparticles have been used as MRI contrast
[...] Read more.
Because magnetic resonance imaging (MRI) contrast agents play a vital role in diagnosing diseases, demand for new MRI contrast agents, with an enhanced sensitivity and advanced functionalities, is very high. During the past decade, various inorganic nanoparticles have been used as MRI contrast agents due to their unique properties, such as large surface area, easy surface functionalization, excellent contrasting effect, and other size-dependent properties. This review provides an overview of recent progress in the development of nanoparticle-based T1-weighted MRI contrast agents. The chemical synthesis of the nanoparticle-based contrast agents and their potential applications were discussed and summarized. In addition, the recent development in nanoparticle-based multimodal contrast agents including T1-weighted MRI/computed X-ray tomography (CT) and T1-weighted MRI/optical were also described, since nanoparticles may curtail the shortcomings of single mode contrast agents in diagnostic and clinical settings by synergistically incorporating functionality. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles 2013)
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